Extinction of laser rangefinder (LRF) pulses by the atmosphere depends on the laser wavelength, weather conditions, and the aerosol concentration along the optical path. The total atmospheric extinction α is the sum of the molecular and aerosol contributions αm and αa. We present simple expressions for αm and αa for wavelengths near 1.44, 1.54, 2.1, and 10.6 μm, which are eyesafe for most LRF applications. Also included are results for 1.06 μm, which although not an eyesafe wavelength is used extensively for LRF applications. The expressions allow the extinction coefficient to be estimated as a function of standard meteorological parameters, assuming horizontal beam propagation at sea level and a homogeneous atmosphere. Measurements of the signal-to-noise ratio of LRF returns from a calibrated target are presented for various weather conditions and wavelengths.